LiFePO4 is a Li-ion positive electrode material that has been favored for its strong abuse tolerance which in turn has been attributed to the nature of the oxygen bonding in the phosphate group. Also, it is desirable to harness the abuse tolerance of a phosphate based cathode in a material that stores more energy. One possibility is to look to higher voltage olivines such as LiMnPO4 4.1 V, LiCoPO4 4.8 V or LiNiPO4 5.1V since the stored energy is proportional to the voltage. LiCoPO4 in particular has the potential to increase energy ˜40% compared to LiFePO4. Furthermore, its electronic structure is more favorable than LiMnPO4 and LiNiPO4 in terms of polaronic conductivity and ability to form polarons, respectively.
However, and even though initial research on LiCoPO4 led to improvements in the rate of discharge, capacity fade has blocked further progress. As such, an improved Li-ion positive electrode material with a high discharge capacity and low capacity fade would be desirable.